Fire retardant thermoplastic polymer compositions of a methyl methacrylate polymer with a copolymer of a halogenated ethylenically unsaturated monomer and a phosphorous containing vinyl monomer

ABSTRACT

Self-extinguishing, thermoplastic polymer compositions are prepared by the intimate admixture of a thermoplastic polymer with a copolymer of a halogen containing ethylenically unsaturated monomer and a phosphorus containing vinyl monomer, particularly a bis(hydrocarbyl)vinylphosphonate. The thus modified thermoplastic polymers display a high degree of flame retardance without any substantial changes in their physical properties including, for example, their clarity and hardness and the resulting compositions may be safely employed in any application requiring their possible exposure to fire or high temperatures.

United States Patent [191.

Kraft et al.

[111 3,725,509 51 Apr.3,1973

[73] Assignee: Stautter Chemical Company, New

York,-N.Y.

[22] Filed: June 23,1970

21 Appl. No.: 49,204

[52] US. Cl. ..260/899, 260/17 R, 260/29.6 MP, 260/29.6 TA, 260/45.7 P,260/73 L,

260/80.71, 260/85.5 XA, 260/86.1' E,

- .260/87.5 A, 260/87.5 C, 260/87.5 R,

260/857 PA, 260/858,260/859 PV, 260/861, 260/862, 260/876'B, 260/878 R,260/879,

. 260/884, 260/885, 260/901 [51] Int. Cl. ..C08f 29/24 [58] Field ofSearch...;..260/884, 885, 901, 29.6 MP, 260/30.6 R, 45.7 P, D1G..24, 899

[56] 7 References Cited UNITED STATES PATENTS 3,489,706 1/1970Mikofalvy. ..260/29.6 MP 3,194,795 7/1965 Friedman ..260/45.7 P 3,227,696 1/1966 Flowers et a1. ..260/85 .7 3,255,276 6/1966 Winter etal... ..260/897 3,544,509 12/ 1970 Carroll et a1. ..260/45.7 P

OTHER PUBLICATIONS Muray, R. .1. Journal of Polymer Science Part C No.16 (1967) pp. l,869-1,886

Primary Examiner-William H. Short Assistant Examiner-L. M. PhynesAttorney-Wayne C. Jaeschke and Martin Goldwasser 57 ABSTRACTSelf-extinguishing, thermoplastic polymer composi tions are prepared bythe intimate admixture of a thermoplastic polymer with a copolymer of ahalogen containing ethylenically unsaturated. monomer and a phosphoruscontaining vinyl monomer, particularly abis(hydrocarbyl)vinylphosphonate. The thus modified thermoplasticpolymers display a high degree of flame rctardance without anysubstantial changes in their physical properties including, for example,their clarity and hardness and the resulting compositions may be safelyemployed in any application requiring theirpossible exposureto fire orhigh temperatures.

10 Clsims, -No Drawings FIRE RETARDANT THERMOPLASTIC POLYMERCOMPOSITIONS OF A METHYL METHACRYLATE POLYMER WITH A COPOLYMER OF AHALOGENATED ETIIYLENICALLY UNSATURATED MONOMER AND A PI'IOSPIIOROUSCONTAINING VINYL MONOMER BACKGROUND OF THE INVENTION 7 Manythermoplastic polymers such, for example, as the homoand copolymers ofmethyl methacrylate, polyolefins, polystyrene andacrylonitrile-butadienestyrene resins are hard and, in many instances,optically clear materials which are widely utilized for the preparationof a broad range of consumer and industrial articles. As normallyprepared, these thermoplastic polymers will ignite and continue to burnupon exposure to flames or high temperatures. However, in manyinstances, particularly where they are being considered for use inbuilding interiors or in applications requiring their prolonged exposureto high temperatures, it is highly desirable that such polymers shoulddisplay fire or flame retardant properties so that they may either meetthe standards set by various building codes or so that they may besafely employed in place of more costly materials.

Prior attempts to provide fire retardant, thermoplastic polymercompositions have involved the use of a variety of extraneous additivessuch, for example, as antimony oxides, halogenated paraffins,halogenated hydrocarbons and low molecular weight phosphate esters.However, the effective utilization of these and other additives hasordinarily required their presence in rather high concentrations whichadversely affected the physical properties of the treated polymers.Thus, the inherent hardness and, in some instances, the clarity of thethermoplastic polymers were particularly prone to deterioration in thepresence of the high concentrations of these additives which werenecessary in order to achieve a self-extinguishing polymer composition.

It is, therefore, the prime object of this invention to provide fireretardant thermoplastic polymer compositions by the use of additiveswhose presence will not adversely affect the inherent physicalproperties such as upon any of their significant physical properties,and

tion display an outstanding degree of compatibility since, as is wellknown to those skilled in the art, physical blends of two or morepolymers are almost always 1 characterized by their inherently poorcompatibility.

hardness and, in some instances, the clarity of the thus modifiedpolymers. It is a further object of this invention to provide a novelclass of copolymers which are particularly useful, as additives, forpreparing fire retardant, thermoplastic polymer compositions. Variousother objects and advantages of this invention will be apparent from thedisclosure thereof which follows hereinafter.

TECHNICAL DISCLOSURE OF THE INVENTION In its broadest aspect, thisinvention resides in the discovery that thermoplastic polymers may berendered fire retardant by the incorporation, thereon, of additivescomprising copolymers of: (l one ormore halogen containing vinylmonomers with (2) one or more phosphorus containing vinyl monomers ashereinafter defined. More particularly, it has now been discovered thatthe use of copolymers of one or more halogen con-taining vinyl monomerswith one or more bis(hydrocarbyl) vinylphosphonates provides the thusmodified polymers with a high degree of fire retardance withoutresulting in any serious deleterious effects The novel copolymerssuitable for use asfire retardant additives for thermoplastic polymersin the process of this invention comprise copolymers of:

1. One or more halogen containing, alpha, betaethylenically unsaturated,i.e. vinyl, monomers including vinyl halides such, for example as vinylchloride, vinyl fluoride and vinyl bromide; halogenated C -C alkylacrylates and methacrylates such, for example, as methylalpha-chloroacrylate and methyl alphabromoacrylate; vinylidene halidessuch, for example, as vinylidene chloride, vinylidene bromide,vinylidene chlorobromide and vinylidene fluoride; halosubstitutednitriles of ethylenically unsaturated carboxylic acids such, forexample, as alpha-chloroacrylonitrile; and the chlorinated styrenessuch, for example, as

alpha-chlorostyrene, .o-chlorostyrene, mchlorostyrene, p-chlorostyreneand 2,4- dichlorostyrene; and

2. one or more bis(hydrocarbyl):vinylphosphonates having the structure:

wherein X is selected from the group consisting of hydrogen, halogen,cyano, aryl suchas'phenyl, C -C alkyl and v g atomsinclusive with theproviso that R and R may be the same, different or conjoint, i.e. R andR may form one single radical.

The use, in this disclosure, of the expression hydrocarbyl" andsubstituted hydrocarbyl groups refers to the radicals obtained upon theremoval of a hydrogen from a hydrocarbon or substituted hydrocarbongroup which may be either an aliphatic or aromatic group. Thesehydrocarbyl groups may be substituted with any non-interfering groups,i.e. witha'ny group which does not interfere withthe polymerization ofthe bis(hydrocarbyl) vinylphosphonate. Such substituent groups include,for example, chloro, bromo, fluoro, nitro, hydroxy, sulfone ethoxy,methoxy, nitrile, ether, ester and keto groups and the like.

Illustrative of such aliphatic groups as are represented by R and R' arealkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl,nonyl, pentenyl and hexenyl groups and all of their respective isomers;cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl and cyclohexenyl groups and the like; while typical arylgroups represented by R and R include phenyl, benzyl, phenethyl,'tolyland naphthyl groups and the like.

' Representative of the above depicted bis(hydrocarbyl)vinylphosphonates are:

Bis(beta-chloroethyl) vinylphosphonate;

Bis(b'eta-chloropropyl) vinylphosphonate;

Bis(beta-chloroethyl) 1-methylvinylphosphonate;

Bis(beta-chloroethyl) 1-cyanovinylphosphonate;

Bis(beta-chloroethyl) l-chlorovinylphosphonate;

Bis(beta-chloroethyl) 1-phenylvinylphosphonate;

Dimethyl vinylphosphonate;

Diethyl vinylphosphonate;

Bis(omega-chlorobutyl) vinylphosphonate;

Di-n-butyl vinylphosphonate;

Di-isobutyl vinylphosphonate;

Bis(2-chloroisopropyl) l-methylvinylphosponate;

Diphenyl vinylphosphonate; and

Bis(2,3-dibromopropyl) vinylphosphonate.

From the above group of bis(hydrocarbyl) vinylphosphonate monomers, itis preferred to employ bis(beta-chloroe thyl) vinylphosphonate inpreparing the novel copolymers of this invention since the lattermonomer is a commercially available material and lower in cost than anyof the other bis(hydrocarbyl) vinylphosphonates. It is to be noted, atthis point, that the use of the term copolymer in this disclosure ismeant to apply to polymers derived from two, three or more distinctmonomer species.

In addition to the above described bis(hydrocarbyl) vinylphosphonates,it is also possible to prepare copolymers useful as flame retardantadditives for thermoplastic polymers by employing: (1) mono(alkyl) acidvinylphosphonates such, for example, as mono(ethyl) hydrogenvinylphosphonate, mono(butyl) hydrogen vinylphosphonate, mono(octyl)hydrogen vinylphosphonate; mono(beta-chloroethyl) hydrogenvinylphosphonate, mono(omega-chlorooctyl) hydrogen vinylphosphonate; (2)mono(cycloalkyl) and mono(aryl) hydrogen vinylphosphonates such, forexample, as mono(cyclohexyl) hydrogen vinylphosphonate, mono(phenyl)hydrogen vinylphosphonate, mono(benzyl) hydrogen vinylphosphonate; (3)bis(cycloalkyl) and bis(aryl) vinylphosphonate such, for example, asbis(cyclohexyl) vinylphosphonate and bis(benzyl) vinylphosphonates; and,(4) bis(alkyl), bis(cycloalkyl), and bis(aryl) allylphosphonates such,for example, as bis(betachloroethyl) allylphosphonates, bis(cyclohexyl)allylphosphonate and bis(benzy1) allylphosphonate as well as mixtures ofany two or more of the above described phosphonate monomers.

The copolymers of this invention may also, if desired, contain one ormore optional comonomers including alpha-olefins such as ethylene,propylene and butylene; vinyl esters of carboxylic'acids such as vinylacetate, vinyl butyrate, and vinyl stearate; the C,C, alkyl esters ofacrylic and methacrylic acid such as methyl methacrylate, methylacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate andlauryl acrylate; aryl, haloand nitrosubstituted benzyl esters of acrylicand methacrylic acid such as benzyl acrylate and 2- chlorobenzylacrylate; ethylenically unsaturated monocarboxylic-acids such as acrylicand methacrylic acids; ethylenically unsaturated dicarboxylic acids,their anhydrides and their C C monoand dialkyl esters such as aconiticacid, fumaric acid, maleic acid, itaconic acid, citraconic acid, maleicanhydride, dib utyl fumarate and monoethyl maleate; amides ofethylenically unsaturated carboxylic acids such as acrylamide andmethacrylamide; vinyl aryl compounds such as styrene and alpha-methylstyrene; nitriles 0f ethylenically unsaturated carboxylic acids such asacrylonitrile and methacrylonitrile; C C, alkyl vinyl ethers such asmethyl vinyl ether, ethyl vinyl ether and stearyl vinyl ether; dienessuch as isoprene and butadiene; and, glycidyl esters of acrylic andmethacrylic acid such as glycidyl acrylate and glycidyl methacrylate,etc. Preferred for use as optional comonomers are methyl methacrylate,acrylonitrile and methacrylonitrile.

The above described copolymers may be prepared by means of anyconvenient polymerization technique known to those skilled in the artsuch, for example, as

by means of a free radical, ionically or Ziegler catalyst initiatedbulk, emulsion, solution or suspension type polymerization technique.

However, for use as flame retardant additives for thermoplasticpolymers, it is preferred that they be prepared by means of a freeradical initiated, suspension polymerization process in an aqueousmedium containing from about 0.01 to 5 percent, as based on the totalweight of the monomer mixture, of a suspension agent such, for example,as gelatin, starch, hydroxymethyl cellulose, hydroxyethyl cellulose,hydroxypropyl cellulose, carboxymethyl cellulose, talc, clay, polyvinylalcohol and the like. As a catalyst for the polymerization, one may usefrom about 0.01 to 5.0 percent, as based on the total weight of themonomer mixture, of a monomer soluble azo or peroxide compound such, forexample, as azobisisobutyronitrile, lauroyl peroxide, benzoyl peroxide,isopropylperoxy dicarbonatc, t-butyl peroxypivalate and the like.Polymerization may ordinarily be initiated by heating the system to atemperature in the rangeof from about l0 to 100C. for a period of fromabout 1 to 30 hours with agitation being applied throughout the courseof the reaction. The resulting product will comprise an aqueoussuspension of the desired copolymers which will be in the form ofparticulate solids having a resin solids content in the range of fromabout 5 to percent, by weight. These copolymer particles will have aparticle size in the range of from about 2 to 500 microns with a rangeof from about 50 to 250 microns being preferred when these copolymersare to be used as additives for preparing flame retardant,,thermoplastic polymers. These copolymers should have a molecularweight, as expressed in terms of theirRelative Viscosity, of from about1.5 to 3.0 when determined, at 25C. with a 1 percent, byweight, solutionof the copolymer in cyclohexanone.

With respect to proportions, these novel copolymers may contain fromabout 2.5 to 99 percent, by weight,

of one or more of the above described bis(hvdrocarbyl) vinylphosphonateswith the balance of the copolymer comprising one or more of the abovedescribed halogen containing, ethylenically unsaturated monomerstogether with from O to about 50 percent, by weight of one of more ofthe above described optional comonomers. Optimum results, as flameretardant additives for thermoplastic polymers, are obtained by the useof copolymers containing from about 2.5 to 60 percent of one or morebis(hydrocarbyl) vinylphosphonates, preferably bis(beta-chloroethyl)vinylphosphonate.

It is to be noted, with respect to the above described proportions forthe composition of the copolymers of this invention, that is has beenfound that it becomes increasingly more difficult to attain goodpolymerization conversion rates as attempts are made to increase theamount of the bis(hydrocarbyl) vinylphosphonate in the resultingcopolymer substantially above a concentration of about 60 percent, byweight. On the other hand, the use of these polymers as flame retardantadditives for thermoplastic polymers becomes progressively moreinefficient when they contain substantially less than about 5 percent,by weight, of one or more bis(hydrocarbyl) vinylphosphonates since theresulting blend will then require the presence of a rather highconcentration of the copolymer in order to attain flame retardancy. Theuse of such high concentrations of these copolymer additives may, inturn, result in some deterioration in the inherent physical propertiesof the thus modified thermoplastic polymer.

Specific copolymer compositions which have been found to provideparticularly good results as additives for the preparation of fireretardant, thermoplastic polymer composition are:

l. a copolymer of vinyl chloride with about to 40 percent, by weight, ofbis(beta-chloroethyl) vinylphosphonate, and t 2. a terpolymer containingabout 10 to 60 percent, by weight, of vinyl chloride, about 10 to 60percent, by weight of vinyl bromide; and about 10 to 60 percent, byweight of bis(beta-chloroethyl) vinylphosphonate.

In all cases, the novel copolymers of this invention have been found toprovide blends with thermoplastic polymers which are characterized bytheir outstanding fire retardancy, their excellent compatibility andtheir retention of physical properties such as hardness, tensile andimpact strengths and clarity in those cases where the initial polymersubstrate is itself clear. As used in this disclosure, the term fireretardant or flame retardant is intended to refer to that particularproperty of a material which provides it with a degree of resistance toignition and burning. Thus, a fire or flame retardant composition is onewhich has a low level of flammability and flame spread. This propertymay be conveniently evaluated by means of anyof the standard flameretardancy tests such, for example, as the ASTM test D-635.

In addition to being used as fire retardant additives for thepreparation of thermoplastic polymer compositions, the bis(hydrocarbyl)vinylphosphonate copolymers of this invention may be used in any of thevarious coating, adhesive, laminating, impregnating and moldingapplications known to those skilled in the art. Thus, they may be coatedupon and/or absorbed by all types of substrates to which it is desiredto impart fire retardant properties. They may, therefore, be used ascoatings, impregnants, fillers, laminants, and adhesives for suchsubstrates as wood; paper; metals; textiles based on either natural orsynthetic fibers or blends I or condensation polymerization techniques.

Any desired thermoplastic polymers may. be blended with the abovedescribed bis(hydrocarbyl) nylphosphonate copolymers in order to preparefire retardant compositions. Such thermoplastic polymersjn: clude:

l. the homopolymer of methyl methacrylate, i.e.

polymethyl methacrylate, as well as copolymers of methyl methacrylatewith minor proportions of one or more alpha, beta-ethylenicallyunsaturated monomers which are polymerizable therewith including: theC,--C

alkyl, cycloalkyl and bicycloalkyl esters of acrylic acid and the C -Calkyl, cycloalkyl and bicycloalkyl esters of methacrylic-acid such, forexample, as ethyl acrylate and methacrylate, butyl methacrylate,ethylhexyl methacrylate, norbornyl acrylate, and 'cyclohexyl acry-.late; vinyl aryl compounds such, for example, as alphamethyl styrene andstyrene; and, nitriles of alpha, betaethylenically unsaturatedcarboxylic acids such, for example, as acrylonitrile andmethacrylonitrile. From the above given group, the use of the C C alkylesters of acrylic acid, particularly ethyl acrylate, and of the C -Calkyl esters of methacrylic acid is preferred; v

2. acrylonitrile-butadiene-styrene resins, commonly referred to as ABS"resins which generally comprise either a mixture of a '60 to" 80140: 'to20 styrenezacrylonitrile copolymer with from about 10 to 40 percent, byweight of a 5 to 40:95 to .60 acrylonitrilezbutadiene copolymer oramixture of a 60 to :40 to 20 styrenezacrylonitrile copolymer with fromabout 10 to 40 percent, by weight, of a graft of the latter copolymeronto polybutadiene;

3. poly(alpha-olefins) such as polypropylene and polyethylene andcopolymers of one or more alphaolefins, such as ethylene or propylene,with a minor proportion of one or more ethylenically unsaturatedmonomers including 4-methyl pentene-l; butene-l; norbornene and itsderivatives; (EPDM) cyclopetadiene; cyclopentene; cyclobutene; vinylacetate; the C -C alkyl acrylate and methacrylate esters; as well asblends of the homo-and copolymers of alpha-olefins with other types ofthermoplastic polymers;

4. polystyrene andcopolymers of styrene or alphamethyl styrene with aminor proportion of one or more ethylenically unsaturated comonomerssuch, for example, as nitriles of ethylenically unsaturated carboxylicacids including acrylonitrile and methacrylonitrile; and C -C alkylesters of acrylic and methacrylic acid such, for example, as methylrnethacrylate an Z-ethylhexyl acrylate; and graft copolymers of styreneor alpha-methylstyrene with polybutadiene and other hydrocarbonelastomers;

5. cellulosic resins including cellulose esters and mixed esters such,for example, as cellulose nitrate, cellulose acetate, cellulosebutyrate, cellulose propionate, cellulose acetate-butyrate, celluloseacetatepropionate and cellulose ethers such, for example, as ethylcellulose; I

6. polyamide resins, i.e. the resins made by the condensation of diorpolyamines with dior polybasic acids or by polymerization of lactams oramino acids. Typical polyamides include: nylon 4 which is made frompyrrolidone; nylon 6 obtained by polycondensation of caprolactam; nylon66 obtained by the condensation of hexamethylene diamine with adidicacid; nylon 610 obtained by the condensation of hexamethylenediaminewith sebacic acid; nylon 7 which is a polymerof ethyl aminoheptanoate;nylon 9 made from 9-aminononanoic acid; and nylon 11 made from 1 l-aminoundecanoic acid;

.7.polyester resins, i.e. the resins produced by the condensation ofsaturated or unsaturated dibasic acids, such as terephthalic, maleic,fumaric, isophthalic, adipic and azelaic acids with dihydric alcoholssuch as ethylene glycol, propylene glycol, diethylene glycol anddipropylene glycol. Where the resin is made with an unsaturated acid, apolymerizable monomer such, for example, as styrene, vinyl toluene,diallyl phthalate, methyl methacrylate; chlorostyrene, alpha-methylstyrene, divinyl benzene or triallyl cyanurate is often included in thecomposition;

8. polyurethane resins, i.e. the resins formed by the reaction between abior polyfunctional hydroxyl con taining compound, such as a polyetheror polyester, and a dior polyisocyanate such as toluene disiocyanate ordiphenylmethane-4, 4-diisocyanate;

9. polycarbonate resins, i.e. the resins derived from the reactionbetween a difunctional alcohol or phenol, such as bisphenol A, andphosgene or an alkyl or aryl carbonate; y, A g

l0. polyacetal resins, i.e. the resins derived from the anionicpolymerization of formaldehyde to obtain a linear molecule of the type-OCH -OCH,O 2"' v I ll. polyphenylene oxide resins made by the oxidativepolymerization of 2,6-dimethylphenol in the presence of acopper-amine-complex catalyst;

12. polysulfone resins, i.e. the resins containing an S linkage asderived from the reaction of sulfur dioxide with olefins such asl-butene or, more preferably, by reaction of bisphenol A with4,4-dichlorodiphenyl sulfone;

13. the acrylate:sytrene2acrylonitrile resins, commonly referred to asASA resins, which comprise a copolymer containing a major proportion ofa C -C alkyl acrylate elastomer upon which is grafted about 80-72percent of the weight of the latter copolymer of a 70-80:30-20styrene:acrylonitrile copolymer.

In effect, one may utilize any thermoplastic polymer, i.e. any polymerthat may be softened by heat and then regain its original properties oncooling, in preparing the fire retardant compositions of this invention.

The actual blending of the copolymer additives of this invention withthe selected polymeric substrate, i.e. with any one or more of the abovedescribed thermoplastic polymers, may be accomplished by means of anyconvenient procedure which will result in an intimate admixture of theadditive within the mass of the substrate polymer. Thus, for example, anaqueous suspension containing the particles of the copolymer additivemay simply be blended or otherwise admixed with the substrate polymerwhich should, preferably, be in the form of an aqueous latex orsuspension. Or, if

desired, the copolymer additive and the thermoplastic polymer substratemay be admixed while each is in the form of a solid powder.

The blending operation may also be carried out by means of a procedurein which the thermoplastic polymer which comprises the substrate isitself polymerized while in the presence of an aqueous emulsion orsuspension or organic solvent solution containing one or more of thepreviously polymerized copolymer additives of this invention.Alternatively,

the bis(hydrocarbyl) vinylphosphonate containing copolymer additive maybe polymerized in a system which contains the previously polymerizedselected thermoplastic polymer substrate in an appropriate physicalform, e.g. as an aqueous suspension or emulsion or as an organic solventsolution.

With respect to proportions, the amount of bis(hydrocarbyl)vinylphosphonate containing copolymer which may be admixed with athermoplastic polymer substrate will depend, primarily, upon suchfactors as the particular phosphonate copolymer and thermoplasticpolymer substrate which are to be blended with one another, the degreeof fire retardancy desired in the resulting blend, the degree ofclarity, hardness and other specific physical properties which aresought as well as other technical and economic considerations known andunderstood by those skilled in the art. However, in order to attain acomposition which will be self-extinguishing, it is generally desirableto introduce an effective concentration of the bis(alkyl)vinylphosphonate copolymer additive which will be sufficient to providethe resulting blend with at least about 0.5 percent, by weight, ofphosphorus and with at least about 10 percent, by weight, of halogen,i.e. chlorine and/or bromine, derived from the halogen containingethylenically unsaturated monomer and also, if possible, from thebis(hydrocarbyl) vinylphosphonate.

The fire retardant, thermoplastic polymer compositions of this inventioncan be prepared so as to contain various optional additives which mayinclude plasticizers such as the alkyl esters of phthalic, adipic andsebacic acids such, for example, as dioctyl phthalate and ditridecylphthalate and aryl phosphate esters such, for example, as diphenyl andtricresyl phosphate, etc.; lubricants and mold release agents such asstearic acid or its metal salts, petroleum based waxes, mineral oils,polyethylene waxes, etc.; and heat and light stabilizers such as barium,cadmium, calcium, zinc soaps or phenates, basic lead compounds,organo-tin compounds, such as dialkyl tin mercaptides and dialkyl tinmaleates, thiolauric anhydride and n-butyl stannoic acid, epoxidizedoils, alkyl diphenyl phosphites, triaryl phosphites, phenyl salicylates,benzophenones and benzotriazoles, etc. For a more complete listing ofplasticizers, lubricants, stabilizers and other functional additives,one may consult Polyvinyl Chloride" by H. A. Sarvetnick published by VanNostrand Reinhold Co., New York, N.Y., in 1969.

The compositions of this invention may also contain fillers, pigments,dyes, opacifying agents, decorative additives such as reflective metalfoilsor flakes, and other imbedded solid objects such as fiber glass,textile fibers, paper, and the like, provided that they do not detractfrom the flame retardancy of these products. In

addition, the compositions may contain other flames retardants such asantimony compounds, halogenated alkyl phosphates or phosphonates, alkylacid phosphates, or small concentrations of phosphoric acid.

The novel fire retardant compositions of the invention, comprisingblends of any of the above described thermoplastic polymers with one ormore of the novel fire retardant additives of this invention, may beutilized in any of the coating, impregnating and especially in themolding applications known to those skilled in the art wherein it isdesired to provide fire retardancy to the resulting end product. Forexample, these compositions may be used for preparing such diverse itemsas calendered films, blow molded bottles, extruded flat bed and blownfilms, extruded and shaped articles such as panels, sheets, rods andtubes, etc. and in carrying out such processes as injection molding,fluidizedbed coat ng, electrostatic powder spraying and rotationalcoating, etc. More particularly, those compositions which are opticallyclear such, for example, as those based upon homoor copolymers of methylmethacrylate or homoorv copolymers of styrene may be utilized forpreparing such articles as lenses, aircraft canopies,

' windows, Windshields, lighting fixtures, and advertising displays.Applications wherein optical clarity is not essential include suchautomotive applications as seat backs, door panels, instrument panels,head rests, arm rests, package shelves, plated hardware, radiatorgrills, fender extensions and liners, wheel covers and gas tanks.Non-automotive applications include their use as structural anddecorative components for both the interiors and exteriors ofconventional houses and mobile homes and as structural and decorativeelements of business machines and electrical appliances.

The following examples will further illustrate the embodiment of thisinvention. In these examples, all parts given are by weight unlessotherwise noted.

EXAMPLE I This example illustrates the preparation of a his(hydrocarbyl) vinylphosphonate copolymer as well as its subsequent usein preparing a fire retardant, thermoplastic polymer composition.

Into a 32 ounce reaction vessel, there is charged 38g ofbis(beta-chloroethyl) vinylphosphonate, hereinafter referred to asbis-beta"; 75g of a 1 percent aqueous solution of methyl cellulose; 0.8gof a 75 percent solution of t-butyl peroxypivalate in mineral spirits;and, 375g of deionized water. The reaction vessel is chilled to atemperature of about C. 1 12g of vinyl chloride monomer is introducedwhereupon the reactor is capped and tumbled end-over-end for 12 hours ina 60C. constant temperature bath.

The resulting aqueous suspension has a resin solids content of percent,by weight, of a 75:25 vinyl chloridezbis-beta copolymer having anaverage particle size of about 200 microns and a Relative Viscosity of1.75 as determined with a 0.lg/deciliter solution of the copolymer incyclohexanone at 25C. After filtering and drying, a small portion of thecopolymer solids is methanol extracted in a Soxhlet apparatus andessentially no free bis-beta is found to have been removed therebyindicating that there is no unreacted bis-beta present in the copolymer.

' Copolymer no.

A total of 44 parts of the above described vinyl chloridezbis-betacopolymer, which is in the form of a dry, particulate mass, isintimately admixed with 56 parts of an :20 methyl methacrylatezethylacrylate copolymer and the resulting mixture, which is found to have aphosphorus content of 1.28 percent, by weight, and a chlorine content of21.8 percent, by weight,,is thereupon fluxed onIt'w'o-roll milloperatingat a temperature of l65C.'A 0.065 inch thick sheet is thenpressed from the fluxed mixture and is found to have excellent color andclarity comparable to that exhibited by a control which comprises a0.065 inch thick sheet prepared by the identical procedure as describedabove using, in this instance, an unmodified batch of the same I h 80:20methyl methacrylatezethyl acrylate copolymer.

The fire retardancy of the control sheet and of the sheet prepared fromthe novel composition of this invention is then evaluated using theprocedure of the ASTM D-635 test. In brief, this test involves preparing5 X k X 0.05 inch specimens from the respective sheets. These specimensare then suspended so that their 5 inches dimension is horizontal andtheir k inch dimension is inclined at a 45 angle. One end of the thussuspended specimen is then contacted, for 30 second periods, with a 1inch high flame from a it; inch diameter barrel bunsen burner fittedwith a 1% inch wide wing top.

As evaluated by means of the latter test procedure, it

is found that the sheet containing the vinyl chloridezbis beta copolymeradditive of this invention is completely non-burning whereas theunmodified control burns at a rate of 1.94 inches per minute until it isentirely consumed.

Comparable results are attained by the use, as fire retardant copolymeradditives, of similarly prepared bis' beta-copolymers in which the vinylchloride is replaced, respectively, with alphachloroacrylonitrile,alpha-chlorostyrene and methyl alpha-chloroacrylate.

EXAMPLE II The suspension polymerization procedure described in ExampleI, hereinabove, is followed in order to prepare the various bis(hydrocarbyl) vinylphosphonate copolymer additives listed below:

Composition by weight 84: l 6 vinyl bromidezbis-beta 2 30:50:20 vinylchloridezvinyl bromidezbis-beta 3 60:20:20 vinyl chloridezvinylbromide:bis-beta 4 82:18 vinylidene chloridezbis-heta Samples of each ofthe above described copolymer additives are then intimately admixed withvarious thermoplastic polymer substrates which include:

Thermoplastic copolymer The resulting blends are then used for thepreparation of 0.065 inch thick sheets by means of the milling procedureset forth in Example I. The fire retardancy of these sheets, as well asof controls which comprise sheets prepared from samples of the variousunmodified thermoplastic polymer substrates, is then evaluated by meansof the procedure of the ASTM D- 635 test. Table l hereinbelow, providesa description of the composition of the various sheets while Table 2describes the results attained in their fire retardancy evaluation.

TABLE N 0. I

Composition of sheets undergoing evaluation Percent Copoly- PercentThennoby wt.

mer by wt. plastic thermo- Percent Percent Sheet addicopolypolymerplastic by wt by wt. numtive mer adsubstrate polymer plioshalo hernumber ditive number substrate phorus gen 1 44 1 66 0. 94 29. 6 2 44 1(i6 1. 17 26. b 3 50 2 50 1.80 27.6 3 36 '2 64 l. 40 18. 2 3 a a 50 1.a3 27. 6 3 50 4 50 l. 33 27. 6 4 50 l 50 l. 20 32. 6 0 l 100 0 ,0 0 2100 0 0 C 0 3 100 0 0 40 0 4 100 0' 0 TABLE NO. 2

Flame Retardancy Evaluation Sheet No. l Completely non-burning 2Completely non-burning I 3 Self-extinguishing as defined by ASTM testD-635 4 Self-extinguishing as defined by ASTM test D-635 5 Completelynon-burning 6 Self'extinguishing as define by ASTM test D-635 7Completely non-burning lC Burns at rate of 1.94 inches/minute untilentirely consumed 2C Burns at rate of 2.2 inches/minute until entirelyconsumed 3C Burns at rate of 2.3 inches/minute until entirely consumed4C Burns at rate of 2.3 inches/minute until entirely consumed The abovegiven data is clearly indicative of the excellent results that areachieved in the flameproofing of thermoplastic polymers with the novelbis(hydrocarbyl) vinylphosphonate copolymer additives of this inventionin a direct comparison with unmodified control speciments, i.e. sheetsnumbers lC 4C, of the identical thermoplastic polymers with which theseadditives are here blended.

Comparable results, with respect to flame retardancy, are achieved usinga copolymer containing 80 parts by weight of vinyl chloride and parts,by weight, respectively of each of the following bis(hydrocarbyl)vinylphosphonate monomers:

bis(beta-chloroethyl) l-cyanovinylphosphonate,

bis(beta-chloropropyl) vinylphosphonate,

bis(beta-chloroethyl) l-phenylvinylphosphonatc, di-n-butylvinylphosphonate and diphenyl vinylphosphonate;

these copolymers being blended with the following thermoplastic polymersubstrates:

an acrylate:styrene:acrylonitrile resin polypropylene,

polyethylene,

l. A fire retardant, thermoplastic composition comprising an intimateadmixture of at least one .thermoplastic polymer of methyl methacrylateor copolymer of methyl methacrylate with a minor proportion of at leastone other alpha, beta-ethylenically unsaturated monomer and a flameretardant amount of a copolymer consisting essentially of:

1. at least one halogen containing ethylenically unsaturated monomerselected from the group consisting of vinyl halides and vinylidenehalides; and, 2. from about 2.5 to about 99 percent by weight of thecopolymer of at least one bis (hydrocarbyl) vinylphosphonatehaving thestructure:

wherein X is selected from the group consisting of hydrogen, halogen,cyano, aryl, C -C, alkyl and wherein R and R are hydrocarbyl up to 18carbon atoms and substituted hydrocarbyl groups with the proviso thatsaid substituted groups are non-interfering which R+s can be the same,different or cojoint.

2. The composition of claim 1, wherein the halogen containing,ethylenically unsaturated monomer of said copolymer is a vinyl halideselected from the group consisting of vinyl chloride, vinyl fluoride andvinyl bromide.

3. The composition of claim 1, wherein the vinylidene halide of saidcopolymer is vinylidene chloride.

4. The composition of claim 1, wherein said copolymer contains fromabout 5 to 60 percent, by weight, of said bis(hydrocarbyl)vinylphosphonate 5. The composition of claim 1, wherein thebis(hydrocarbyl) vinylphosphonate of said copolymer isbis(beta-chloroethyl) vinylphosphonate.

6. The composition of claim I, wherein, said copolymer is a copolymer ofvinyl chloride and from about 10 to 40 percent, by weight, ofbis(betachloroethyl) vinylphosphonate.

7. The composition of claim 1, wherein said copolymer is a copolymer offrom about 10 to 60 percent, by weight, of vinyl chloride; from about 10to 60 percent, by weight, of vinyl bromide; and, from about 10 to 60percent, by weight, of bis(beta-chloroethyl) vinylphosphonate.

8. The composition of claim 1, wherein said thermoplastic polymer ispolymethyl methacrylate.

, 9. The composition of claim 1, wherein said ther-'

2. The composition of claim 1, wherein the halogen containing,ethylenically unsaturated monomer of said copolymer is a vinyl halideselected from the group consisting of vinyl chloride, vinyl fluoride andvinyl bromide.
 2. from about 2.5 to about 99 percent by weight of thecopolymer of at least one bis (hydrocarbyl) vinylphosphonate having thestructure: wherein X is selected from the group consisting of hydrogen,halogen, cyano, aryl, C1-C8 alkyl and , wherein R and R'' arehydrocarbyl up to 18 carbon atoms and substituted hydrocarbyl groupswith the proviso that said substituted groups are non-interfering whichR+s can be the same, different or cojoint.
 3. The composition of claim1, wherein the vinylidene halide of said copolymer is vinylidenechloride.
 4. The composition of claim 1, wherein said copolymer containsfrom about 5 to 60 percent, by weight, of said bis(hydrocarbyl)vinylphosphonate.
 5. The composition of claim 1, wherein thebis(hydrocarbyl) vinylphosphonate of said copolymer isbis(beta-chloroethyl) vinylphosphonate.
 6. The composition of claim 1,wherein said copolymer is a copolymer of vinyl chloride and from about10 to 40 percent, by weight, of bis(beta-chloroethyl) vinylphosphonate.7. The composition of claim 1, wherein said copolymer is a copolymer offrom about 10 to 60 percent, by weight, of vinyl chloride; from about 10to 60 percent, by weight, of vinyl bromide; and, from about 10 to 60percent, by weight, of bis(beta-chloroethyl) vinylphosphonate.
 8. Thecomposition of claim 1, wherein said thermoplastic polymer is polymethylmethacrylate.
 9. The composition of claim 1, wherein said thermoplasticpolymer is a copolymer of methyl methacrylate with a minor proportion ofa C1-C8 alkyl acrylate.
 10. The composition of claim 9, wherein saidthermo-plastic polymer is a copolymer of methyl methacrylate with aminor proportion of ethyl acrylate.